8 3/4 - Yoke u-joint caps help

Posted By: W5Duster436

8 3/4 - Yoke u-joint caps help - 07/09/08 01:23 AM

So I spent about an hour or so changing the differential in my 8 3/4 housing and noticed when I went to put my u-joint caps on that it seems this particular yoke does not have threads???

Are there two different styles of yokes that take two different types of u-joint caps?

Seems that I have seen some before that were u-shaped and threaded and went through the yoke but the ones I had were just caps with 4 small bolts. It doesn't seem like mine have any marks on the back side of the yoke where nuts have been tightened.. Help!!!

Posted By: 440newport

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 01:27 AM

Is the yoke drilled all the way through? If there are no threads I would guess somebody drilled it out for for the U bolt style caps. Maybe you could tap the threads for new bolts if there's enough meat there?

Posted By: W5Duster436

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 01:30 AM

That's all I could figure is that they were drilled but never used yet since there are no marks on the backside of the yoke where the nuts would have gone.

It seems that I recall the caps on my dana being the u-bolt with nuts but I am not sure without going outside to look. I just want to be sure that those will work with an 8 3/4 yoke also. I guess I'll have to go measure from the outside of the cap all the way through to the back.

Posted By: W5Duster436

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 01:53 AM

I went out and measured from the cap to the back of the yoke and it looks to be about 1 7/8" so I would need a u-bolt about 2.125 or so? Anybody have a u-bolt they can measure to check? This is a 489 case with a 7290 yoke? It takes the larger u-joint I believe and seemed to be the exact same yoke as in the 741 I took out but no threads..

Attached picture 4539539-yoke.jpg

Posted By: B5 Bee

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 02:29 AM

The only yokes I've seen that can take a U-bolt is aftermarket.
Sounds like it has been drilled out for the Moroso cap and bolt kit. That's what you may have to get if you don't want to change yokes.
They look like this, except the ones for the 7290 will be blue,

Posted By: W5Duster436

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 02:34 AM

Yeah I looked at my Dana and I cannot for the life of me figure out where I used those u-bolt caps on. I thought it had them but it has the regular strap with bolts.

I can't ever win I tell ya..

Thanks for the info.. I'll see if those give dimensions on moroso's site.

I saw u-bolts on denny's driveshaft site too. I was hoping Cass would see this post and respond..

Posted By: B5 Bee

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 02:45 AM

Only '66-'67 Dana 60s came with U-bolts, '68-up used the straps. The '66-'67 also used a Spicer 1330 joint instead of the 7290. IIRC, the 1330 caps have a smaller diameter than the 7290, they're about the same as the 7260. The yokes with U-bolt I've had were 5/16", can the 7290 yoke be drilled big enough and not be too thin?

Posted By: W5Duster436

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 02:54 AM

Quote:

Only '66-'67 Dana 60s came with U-bolts, '68-up used the straps. The '66-'67 also used a Spicer 1330 joint instead of the 7290. IIRC, the 1330 caps have a smaller diameter than the 7290, they're about the same as the 7260. The yokes with U-bolt I've had were 5/16", can the 7290 yoke be drilled big enough and not be too thin?

I bet it was my buddy's '67 GTX that had the u-bolts I am thinking about..

No, I think I am probably stuck with either u-bolts or those moroso caps you are referring to. They look pretty good thats for sure. I guess I can call [Email]Tom@RT[/Email] tomorrow and have him give me measurements for the u-bolt type for a 7290 setup. Like my picture said it looks like they'd have to be a little over 2" to work and get the washer and nut on. I was hoping to find out the length of those moroso setups too. Hopefully someone will chime in that knows for sure. I hate to waste another 25 bucks on those morosos if they won't work.

Maybe the Mopar Performance P3690774 would work but for the price it seems the moroso units would hold up better.

Posted By: B5 Bee

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 04:36 AM

The factory U bolt type yoke for a 8.75 rear is '66-'67 only. Used on some or most Hemi automatics and maybe some '67 440 autos. It also uses the Spicer 1330 joint like the '66-'67 Dana. You would have to use that yoke and a 7290/1330 conversion joint. Also the 8.75 yoke is kinda rare and the U bolts from one would not work on the 7290 yoke.
I don't think there's enough meat around the 1/4" hole on the 7290 yoke to drill/tap to use 5/16" bolts (instead of the 1/4") or a 5/16" U-bolt.
Why do you think the Moroso 85820 girdle wouldn't work, it's for the 7290 yoke.

Posted By: JohnRR

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 04:53 AM

i don't think there is a u bolt that will work wit hthat butchered yoke , if it were me i would replace the yoke .

the moroso caps can have issues if you have incorrect pinion angle and the axle winds up too much

Posted By: DoctorDiff

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 05:25 AM

Imperial (CV joint type) 8 3/4" yokes can also be used with U-bolts.

Posted By: DoctorDiff

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 05:25 AM

If you can post a picture of your yoke, I can identify it.

Posted By: W5Duster436

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 12:36 PM

It is the exact same yoke that was on my original 741 case but just isn't threaded. It is 2 5/8" from the inside of the perches. Which would make it the 7290 style eh? Looks just like this...

Attached picture 4540253-yoke.jpg

Posted By: therocks

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 12:36 PM

As DR Diff said Imperial 8 3/4s camr with the u bolts.I have at least 2 from my 69 70 Imps that I scrapped.Rocky

Posted By: W5Duster436

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 01:23 PM

Called Denny's driveshaft and they said to just get the moroso cap kit or just buy bolts/nuts to use with my strap. I guess I'll just get the moroso caps and try them out.

Posted By: W5Duster436

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 01:52 PM

Quote:

i don't think there is a u bolt that will work wit hthat butchered yoke , if it were me i would replace the yoke .

the moroso caps can have issues if you have incorrect pinion angle and the axle winds up too much

John it's all stock diff and nothing has been changed. I probably shouldn't have too many issues as it won't be at the track wheel hopping hopefully.

Posted By: CJK440

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 02:05 PM

I would use the stock steel straps and go get yourself some good socket head cap screws and nylock nuts.

Lots of bad stories with those alum caps.

Posted By: Ronnman

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 02:25 PM

The past owner of my old 73 Challenger had drilled out the yoke and installed grade 8 capscrews and nylok nuts. Car had a mild 440 and 741 pumpkin. Never had any issues with the rearend. I also recommend using straps and through bolts/nuts.
Ron

Posted By: W5Duster436

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 02:32 PM

I guess this would definitely be the cheaper/easier way to go. I guess I'll have to figure out what size they are. 1/4-28 is fine thread right? I guess 1.5" long would be my guess..

What is the thread size of the original style bolts?

Posted By: CJK440

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 03:23 PM

The thread won't matter as long as you get the matching nuts.

Do you have a place local that sells bolts, you can just bring the whole deal.

Posted By: DoctorDiff

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 03:59 PM

Don't use the Moroso caps. They often contact the driveshaft and create carnage.

Posted By: mod5v

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 04:01 PM

maybe u could use the F*%$D 9" u-bolts. There are several diffrent sizes. used them on our dirt track cars and never had a failure.

Posted By: W5Duster436

Re: 8 3/4 - Yoke u-joint caps help - 07/09/08 06:42 PM

Since I don't have the original bolts with me are they 1/4" bolts? If so I guess I can get some 1.75" 1/4-28 grade 8 cap screws and try them.

So in my above picture the length is around 1 7/8 total so I am assuming that half the cap is .5625 (1.126 diameter) subtracted from 1.875 (1 7/8 I measured) which leaves 1.312". I guess adding in the thickness of the cap and needing some space for the nuts will leave me to get 1.75" or 2" long bolts.

Sound right? Not sure the have 1.75" long cap screws but I guess I'll call around.